Answer:
the required concentration is 1.52 M
2 HCl + Na2CO3 -----> CO2 + H2O + NaCl
2 moles HCl reacts to form 1 mole of CO2 .
no. of moles of CO2 = 20.1/ 44.1 = 0.455
no. of moles of HCl = 0.455* 2 = 0.911 mole (molar ratio =2 from equation)
con. of HCl =no. of moles/volume in liter
=0.911/ 0.597 = 1.52 M